Patent GB-320364-A (GB)
Title: Improvements in or relating to electrical indicating, measuring, recording or controlling apparatus
IPC: G01R11/56
Filed: 1928-04-11
Abstract: 320,364. Dance, H. E. April 11, 1928. Special quantities, registering. - Volt-amperes are indicated, measured and recorded, or relays controlled in response thereto, by means of a device consisting of two mutually inductive windings, one of which is continuously rotated or oscillated independently of power factor varia tions, so as to vary cyclically the phase relation of the electromotive forces in the two windings such that they are in phase once during each cycle. The device may be combined with meters or with a relay, the electrical connections to the mains being in all cases current and potential, made either direct or through transformers, impedances, &c. When the device is continuously oscillated, a record in one direction only is made. The non-driven member of the device may be restrained from rotating by springs &c. up to its maximum restraint, whereafter the restraining force is caused to assist the measuring or controlling force on the return movement. Maximum volt-amperes on a time basis, instantaneous watts or volt-amperes, direction of power flow and power factor may be recorded or deduced, the chart being driven at constant speed or given a step-by-step motion. The torque between the two members of the device can be employed to pull the driven member into synchronism with the driving motor, or it may be employed to cause a relative continuous rotation between the two members when combined with a meter or relay, the relative rotation being controlled by known escapement, or brake mechanism. In one arrangement, Fig. 2, the winding member A<2> is continuously driven through gearing by a motor M and the other winding member B<2> is connected to the current winding of an integrating-meter D<2>. Pawl-and-ratchet mechanism is provided for connecting the meter rotor d<2> with the counter d<3>, the pawl mechanism being arranged to indicate either kilo-volt-amperes or maximum deflection. The member B<2> can be restrained bv gravity, spring, or by eddy current braking and may have direct connection with an indicator spindle. Stops may be provided to allow the restrained member to rotate in one direction only. In one such arrangement, Fig. 10, the member A<10> is driven by a motor F and the member B<10> is controlled by a spring C<1>. During each complete cycle, the torque between the members A<10>, B<10> reaches a maximum value and overcomes the controlling torque. The stop b<1> thereupon operates the counter drive d' and the motion of the member B<10> may be caused to adjust the tension of the spring C<1>. In Fig. 9, the member B<9> is connected to two single-phase induction meters D, D<1> provided with a common flywheel rotor R, the member A<9> being driven by a synchronous motor F. The torque on the flywheel may comprise a small component for overcoming friction. Positive and negative directions of torque are transmitted to the counter by pawl- and-ratchet gear. When recording-meters are employed, the chart can be driven forward continuously or step-by-step, for example, in Fig. 11, a. single-phase recording wattmeter is provided with a chart which is given a step-by-step motion by cams d<3>, d<4> on the member A<11> engaging with a lever d<2> connected to the chart mechanism, the arcs d<6> recording watts and the points of maximum deflection d<5> volt-amperes.